In addition to compelling the modernization of structures and infrastructures, the multiplication of people and business activity in nineteenth and early twentieth century cities necessitated the reorganization of commercial, industrial, and residential land use patterns. In the early nineteenth century, American cities were little more than small towns, most of their land being given over to compact mixtures of middle class homes, workers' cottages, boardinghouses, stores, artisans' and blacksmiths' shops, saloons and coffee shops, stables, lumber yards, ropewalks, distilleries, and small factories, all within walking distance of one another. Economic and population growth necessitated a reorganization of this mixed pattern of land usage that was as fundamental as the transformation it required of the built environment. The cities were initially so small and geographically undifferentiated that they simply could not physically accommodate the great influx of people flowing into them without undergoing far-reaching spatial redevelopment.

The changes can be summarized as follows. First, population and economic growth required the territorial expansion of the densely built up sections of the cities, together with an overall intensification of land use in these areas. Physically enlarging the areas of dense usage was especially necessary, for without such expansion, growth could be accommodated only through crowding and, in the absence of adequate structures and infrastructures, overcrowding, to the detriment of public health, local business conditions, and the general quality of urban life. Both vertical and horizontal expansion provided relief from the pressures on the land.

Fires were common in American cities in the nineteenth and early twentieth centuries. Their destructiveness constantly prompted environmental redevelopment on a small scale. Great fires like those in Chicago, Boston, and Baltimore took place comparatively rarely. They were, however, common enough to constitute an important natural force for urban renewal on a major scale in many large cities in this period. As this study indicates, they temporarily eliminated an important barrier to change, the physical durability of structures. This lifted a wide variety of other powerful demand- and supply-side barriers to environmental improvement, stimulating extensive structural and infrastructural redevelopment and, depending on the timing and extent of the destruction, considerable spatial redevelopment as well.

Clearly, great fires played an important part in the environmental development of many American cities. The purpose of this book has not been to identify and analyze precisely the role that these disastrous conflagrations played in the process of city growth, however. Instead, its goal has been to explain the frictions impeding the process of environmental development, the difficulties of environmental adaptation, which account for the terrible fire, pollution, congestion, housing, and other environmental problems cities suffered in this era. The great fires and reconstructions of Chicago, Boston, and Baltimore have merely provided the historical context in which these barriers to improvement have been described.

On the evening of Saturday, November 9, 1872, a fire broke out at the corner of Summer and Kingston Streets in Boston. It was first noticed as a reddish glow in the basement windows of the building shortly after 7:00 p.m. and was soon seen “roaring up the elevator” to the upper stories. By 7:20 the flames had attracted a crowd of onlookers, but the first alarm was, inexplicably, not sounded until 7:24. By the time fire companies finally began to arrive, the building was “one vast furnace,” the heat so intense that no one could get within fifty feet of it and so powerful that the building's granite walls began to explode, sending stony fragments flying in every direction in pieces up to thirty pounds in weight.

From the start, the Fire Department found itself no match for the heat and the flames. The delay in sounding the first alarm was only one of its problems. For a variety of reasons, the Department had no fire houses in the central district where the fire broke out. Ordinarily, it had gotten around this difficulty by dispatching several fire steamers to a blaze whenever a first alarm in the business area came in. On November 9, however, most of the horses in Boston were suffering from a plaguelike disease called epizootic. Half the Department's horses were too sick to stand without support, and almost all the rest were too weak to be put into service.